The present invention relates to photochromic polymeric articles which are intended for use as eyeglass frames and to a method of making the articles. Preferred embodiments of the present invention relate to photochromic eyeglass frames incorporating interchangeable photochromic tubing and to photochromic eyeglass frames having photochromic lenses.
Ophthalmic and planar lenses having a photochromic nature have been known for many years. Such lenses offer both functional and aesthetic features. There has been much research and development in the field of polymeric or plastic lenses with photochromic molecules imbibed therein. Of course, eyeglasses having photochromic lenses have been popular because they have the ability to adjust the density of their tint. They are quite transparent and can be worn during low light conditions but they darken when exposed to sunlight or UV light. It is, of course, the photochromic material which has been added to, or coated onto, the lens which changes state under different light conditions to give the lens its photochromic nature.
Although plastic lenses with photochromic characteristics are well known and are advantageous, it would be desirable if improvements could be made relating to the aesthetic nature of the frames which hold the lenses. Plastic frames are relatively light in weight and can be flexible and resistant to breaking. In particular, it would be advantageous if frames could themselves be provided with a photochromic nature. It would be even more advantageous if the color of the frames could be readily changed as desired by the wearer to match, for example, clothing. It would be still more advantageous if the frames and lenses could be made to color match the clothing without changing the lenses or frames.
There remains a need for improvements in incorporating photochromic molecules into plastic articles such as eyeglass frames. The photochromic molecules used in plastic lenses are relatively large in size and are difficult to incorporate into a polymerized plastic polymeric matrix. Difficulties also arise if the polymeric matrix interferes with the changing of states of the photochromic molecule. In short, there remains a need for techniques or methods for providing articles such as eyeglass frames with photochromic characteristics. There is a need for a processes that provides large enough spaces within a substrate to accept relatively large photochromic molecules and allow the molecules to freely change state to thereby exhibit the full range of their photochromic performance. Furthermore, there remains a need for low cost methods. And there remains a need for further improvements in the longevity of the photochromic characteristic.
The present invention provides an improved method for imparting photochromic qualities to eyeglass frames. Some of the methods of this invention can be used in a small optical laboratory without use of complex or expensive equipment or process steps to provide photochromic eyeglass frames that rapidly change state, are resistant to damage due to heat or light, and have long life expectancies. Further understanding of this invention will be had from the following disclosure taken in conjunction with the claims.